The invention relates generally to polycarbonate-epoxide polymers and a method of making the same. More particularly, this invention relates to a polycarbonate-epoxide polymer made from the reaction of oligomeric or polymeric carbonate groups with mono or multifunctional epoxides in the presence of a catalyst, preferably quarternary ammonium salts.
Polycarbonates are well known engineering thermoplastics having high performance characteristics. Polycarbonates are tough, rigid, dimensionally stable and have outstanding impact strength. It will be appreciated that polycarbonate polymers are widely used as glazing materials because of their clarity and toughness. Unfortunately, such optically clear sheets and other articles of polycarbonate can be rather easily scratched and marred.
This problem may be overcome by applying a protective coating over the polycarbonate made from a harder, more mar resistant material such as epoxy. It would be particularly advantageous to effect chemical bonding between the epoxy cover layer and the polycarbonate base so as to form a polycarbonate-epoxide polymer. In addition, such polycarbonate-epoxy polymers would be exPected to exhibit unusual combinations of ductility, toughness and temperature resistance. However, polycarbonate epoxide polymers of this type have never been commercialized although various attempts have been made to combine polycarbonates and epoxy resins.
U.S. Pat. No. 4,746,725 to Evans et al discloses the preparation of a cyclic polycarbonate-polyepoxide product. Evans et al discloses the reaction at an elevated temperature, in the presence of a polycarbonate formation catalyst, of a composition comprising cyclic polycarbonate oligomers with at least one polyepoxy compound.
U.S. Pat. No. 3,098,056 to Schnell et al discloses a thermoset composition prepared from linear polycarbonates and epoxy polymers. Similarly, U.S. Pat. No. 3,220,974 to Fox relates to epoxidized polycarbonate compositions containing dihydric phenol as a constituent thereof. U.S. Pat. No. 3,261,808 to Schnell et al also relates to the preparation and curing of polycarbonates containing epoxy end groups.
U.S. Pat. No. 3,258,356 to Caldwell et al describes a coating material comprised of an admixture of cured epoxy resin and polycarbonate resin.